Conventionally, there is a fuel cell system that uses odorized fuel gas as a technique for making hydrogen gas leakage sensible in the fuel cell system. Furthermore, as the fuel cell system that uses odorized fuel gas, there is a fuel cell system that has an expanded range of capability of sensing fuel gas leakage by disposing an odorant removal section on a fuel offgas passage that lets fuel offgas discharged from a fuel cell go therethrough rather than on a fuel gas passage that lets fuel gas go therethrough to the fuel cell as is conventionally done (see Patent Document 1).
Patent Document 1: Japanese Patent Publication No. 2004-134273